Relatively fire-resistant homes can ignite during low-intensity wildfires if a path of combustible material, such as fences, stairs, decks, or support beams lead the fire to the home. Image from Texas Forest Service report about fires in 2011.
This is a portion of an article first published at Headwaters Economics in July, 2022. It is used with permission here.
Increasing home loss and growing risks require reevaluating the wildfire crisis as a home-ignition problem and not a wildland fire problem. A home’s building materials, design, and nearby landscaping influence its survival. Together with the location, arrangement, and placement of nearby homes, constructing a wildfire-resistant home is critical in light of rising wildfire risks. This report compares the cost of constructing a home to three different levels of wildfire resistance in California.
California is a leader in the country with a statewide building code and other property-level vegetation requirements addressing wildfire impacts to the built environment. Applicable to all new developments located in State Responsibility Areas (SRAs) and the highest fire severity zones in Local Responsibility Areas (LRAs), California’s Building Code Chapter 7A is intended to reduce the vulnerability of homes to wildfire.
Yet given the magnitude of California’s wildfire risks and increasing home development in wildfire-prone areas, constructing a home beyond Chapter 7A requirements may be needed to ensure greater wildfire resistance. Understanding the comparative costs of wildfire-resistant home construction in California can inform future wildfire policy and decision-making.
This report compares the costs for constructing three different versions of a wildfire-resistant home in California:
Baseline home compliant with the minimum requirements of Building Code Chapter 7A;
Enhanced home augmenting Chapter 7A requirements with a vertical under-deck enclosure around the perimeter of the deck and a noncombustible zone around the home (0 to 5 feet), including under the deck and extending five feet out from the deck perimeter; and,
Optimum home constructed to the most stringent, fire-resistant options (e.g., use of a noncombustible material), or in some cases, a “Code plus” option (an option not currently included in Chapter 7A). Optimum performance levels were selected based on recent research findings and best judgment.
Building materials and assemblies for five primary home components were considered, including:
Roof – roof covering, vents, roof edge, and gutters (including gutter covers and drip edge)
Under-eave area – eaves, soffit, and vents
Exterior wall – siding, windows, doors, trim, and vents
Attached deck – horizontal surface area, rails, and under-the-deck footprint
Near-home landscaping – the immediate five-foot perimeter around the home and attached deck (including mulch and fencing)
Cost estimates for individual building materials were provided through RSMeans, a national database of construction costs for residential, commercial, and industrial construction. Cost estimates included building material, labor, equipment, and contractor overhead costs such as transportation and storage fees.
In northern and southern California, building an Enhanced wildfire-resistant home increased construction costs by approximately $2,800 over the Baseline home. Constructing a home to Optimum wildfire resistance increased overall costs by $18,200 in northern California and by $27,100 in southern California.
Although the Optimum home was more expensive to build, it is likely that the increased costs will return greater long-term benefits in energy efficiency and durability. The roof, exterior walls, and near-home landscaping added the largest proportional increases to building costs. Each of the five components is described in more detail below.
Firefighting agencies need to make changes to deal with the the new normal
Fig. 9 from the study below showing the proportions of heat detected on wildfires at night, vs. during the day. The MODIS (black) time series spans 2003–2020 and the VIIRS (red) time series spans 2012–2020. The horizontal dotted line at 28% indicates the CONUS-wide value detected by MODIS from 2003–2020.
In a study of wildfires in the conterminous United States from 2003 to 2020 researchers found that while fire activity increased during the day in the 18-year period, it increased even more at night.
Heat sensing data from satellites showed significant increasing trends in nighttime wildfire fire activity, with a +54%, +42% and +21% increase in the annual nighttime sum of Fire Radiative Power (FRP), annual nighttime active fire pixel counts, and annual mean nighttime per-pixel values of FRP, respectively, in the latter half of the study period. Activity during the day increased also, with rates of +36%, +31%, and +7% respectively.
Analysis of coincident 1000-hour fuel moistures indicated that as fuels dried out, satellites detected increasingly larger and more intense wildfires with higher probabilities of nighttime persistence.
The reason wildfires typically exhibit less activity at night is due to diurnal changes in weather. Nighttime generally brings lower temperatures, higher relative humidity, decreasing winds, and higher fuel moistures in light fuels.
But a warming climate with occasional multi-year droughts and higher temperatures can lead to nighttime higher temperatures and lower humidities. Drought will lower the fuel moistures in live and dead vegetation. These changes can result in fuels at night remaining available for significant and continuous fire spread. This is causing wildfires to burn with more intensity, spread more quickly, and have more resistance to control 24 hours a day.
About 15 to 20 years ago firefighters could usually count on wildfire activity slowing significantly at night as long as the wind was not extreme. Night shift crews could make good progress constructing direct fireline near the edge of fires. In the last few years weather and fuel conditions that permit direct attack by ground personnel, day or night, are less common. Fires are getting larger. Megafires that blacken 100,000 acres are no longer rare.
So now what?
As fires show increasing resistance to control we need to ramp up our fuel treatments, including prescribed fires, by a factor of 10. Less than full suppression of carefully selected fires when the season-ending weather event is on the horizon can have a place also, if they are very carefully planned and actively tracked and managed using all of the predictive tools available run by very smart, experienced personnel.
Uncontrollable extreme wildfires are inevitable; however, by reducing home ignition potential within the Home Ignition Zone we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem. Unfortunately, protecting communities from wildfire by reducing home ignition potential runs counter to established orthodoxy.
We also have to realize that the fire suppression manpower staffing model that was created 50 years ago is obsolete. The agencies that fight wildfires, especially the federal agencies, need to increase the numbers of Interagency Hotshot Crews and engine crews. The crews must be configured and managed to allow personnel to have a reasonable amount of down time at the home unit even during the busiest times of the fire year. They can’t be away from home 90 percent of the time and expect to have a decent work/life balance. One National Forest will begin a pilot program in 2022 increasing the sizes of Hotshot and Engine crews to 30 and 10 people, respectively. This is intended to improve work/life balance and increase the availability of resources.
The reforms in the just-passed infrastructure bill to improve the pay and working conditions of firefighters must be implemented immediately. Slow-walking those improvements, a tactic too often used by the Federal agencies, should not be tolerated.
Technology needs to be adopted to make firefighting more safe and efficient. Firefighters down to the crew supervisor level should have access to real time data about the location of the fire and other firefighting resources 24 hours a day. Communications capabilities need to be robust and bomb proof.
On the afternoon of November 16, 2021 we initiated a 24-hour online poll on Twitter, asking for firefighters’ observations about nighttime wildfire activity.
Question for experienced wildland firefighters.
In the last 7 years on large wildfires, have you seen typical fire activity at night, more nighttime fire activity, or less nighttime fire activity, compared to 8 to 20 years ago?
The blaze in Northern California destroyed 18,804 structures, most of which were in Paradise
Aerial image showing a portion of Magalia just NW of Paradise, illustrating a gradient of fire damage to overstory vegetation with distance from destroyed homes. At least in some areas, burning homes may have influenced the effects to overstory vegetation more so than burning overstory vegetation influenced the outcome to homes. Photo: Owen Bettis, Deer Creek Resources.
In a paper published October 4, 2021, researchers analyzed the structures that were destroyed and those that survived the Camp Fire that ran through the city of Paradise, California in 2018. They considered at least four primary characteristics of structures:
Were they built before or after the adoption in 2008 of Chapter 7A of the California Building Code which requires certain fire resistance measures, including exterior construction materials used for roof coverings, vents, exterior walls, and decks and applies to new construction of residential and commercial buildings in designated fire hazard severity zones.
Distance to nearest destroyed structure.
Number of structures destroyed within 100 meters.
Pre-fire overstory tree canopy within 100 meters
They found that the last three criteria were the strongest predictors of survival. Homes more than 18 meters from a destroyed structure and with less than 53 percent pre-fire overstory canopy within 30 to 100 meters survived at a substantially higher rate than homes in closer proximity to a destroyed structure or in areas with higher pre-fire overstory canopy. Most fire damage to surviving homes appeared to result from radiant heat from nearby burning structures or flame impingement from the ignition of near-home combustible materials. The researchers concluded that building and vegetation modifications are possible that would substantially improve outcomes. Among those include improvements to windows and siding in closest proximity to neighboring structures, treatment of wildland fuels, and eliminating near-home combustibles, especially within 1.5 meters of the structure.
The authors noted that while 7a includes requirements not found in many building codes, a few others are more complete incorporating multiple construction classes based on anticipated radiant heat, flame, and ember exposure levels. For example Chapter 7A does not consider the interaction between components such as siding, window, and the under-eave area on an exterior wall.
There is an opportunity for much needed improvement in both current building codes and how we live in wildfire prone WUI areas.
Below is the complete Conclusion section from the research.
Conclusions
The results of this study support the idea that both proximities to neighboring burning structures and surrounding vegetation influence home survival with wildfire. Denser developments, built to the highest standards, may protect subdivisions against direct flame impingement of a vegetation fire, but density becomes a detriment once buildings ignite and burn.
Recent examples of losses in areas of higher density housing include the wind-driven 2017 Tubbs Fire in northern California, where house-to-house spread resulted in the loss of over 1400 homes in the Coffey Park neighborhood (Keeley and Syphard 2019), and the wind-driven 2020 Almeda Fire in southern Oregon, which destroyed nearly 2800 structures, many in denser areas in the towns of Talent and Phoenix (Cohen and Strohmaier 2020). Once fire becomes an urban conflagration, proximity to nearby burned structures becomes especially important because occupied structures contain significant quantities of fuel, produce substantial heat when burned, and are a source of additional embers. For density to be protective, home and other structure ignitions would need to be rare.
Fifty-six percent of homes in Paradise built during or after 2008 did not survive, illustrating that much improvement is needed in both current building codes and how we live in wildfire prone WUI areas before proximity to nearby structures becomes a benefit rather than a vulnerability. The threat posed by nearby burning structures as well as our finding of an apparent strong influence of vegetation 30–100 m from the home—a distance that in most cases encompasses multiple adjacent properties—demonstrates that neighbors need to work together to improve the overall ability of homes and communities to resist wildfire exposures.
To maximize survivability, homes need to be designed and maintained to minimize the chance of a direct flame contact, resist ember ignition, and survive extended radiant heat exposure. Our analyses demonstrating the strong influence of nearby burning structures on home survival suggests improvements to resist radiant heat exposures may be warranted in the California Building Code—i.e., increasing the standards for buildings within a certain minimum distance of other structures.
Some possible improvements might include noncombustible siding with rating minimums tied to proximity to other structures, both panes in windows consisting of tempered glass, or installation of deployable non-combustible shutter systems. Additionally, certain options for complying with Chapter 7A are better for resisting radiant heat and flame contact exposures and could minimize fire spread to other components. Whereas the International Code Council’s Wildland Urban Interface Building Code (International Code Council 2017) provides three ignition-resistant construction classes to allow for material restrictions as a function of exposure level, Chapter 7A consists of one level, so is binary in nature in that a building either needs to comply, or it does not. The Australian building code for construction in bushfire prone areas, AS 3959 (Standards Australia 2018), incorporates six different construction classes based on anticipated radiant heat, flame, and ember exposure levels. Interaction between components, for example, siding, window, and the under-eave area on an exterior wall, is not considered.
Our summary of damaged but not destroyed homes in Paradise was in line with other reports showing a high proportion of home ignitions indirectly resulting from embers (Mell et al. 2010). Embers frequently ignited near home combustibles such as woody mulch, fences, and receptive vegetative fuels with flames and/or associated radiant heat then impacting the home itself, supporting awareness of the importance of combustibles within the first 1.5 m (5 ft) of the building on home survival.
A re-interpretation of defensible space fuel modifications is needed to increase the building’s resistance and exposure to embers and direct flame contact, especially in the area immediately around a building and under any attached deck or steps. This does not diminish the value of defensible space fuel modifications 9 to 30 m (30 to 100 ft) away from the home, which not only reduces fuel continuity and the probability of direct flame contact to the home, but also provides firefighters a chance to intervene.
While our data show a relationship between home loss and vegetative fuels (high pre-fire overstory canopy cover likely associated with a greater litter and woody fuel abundance, as well as other wildland understory vegetation) that can contribute to fire intensity and ember generation, the WUI fire loss issue has been described as home ignition problem more so than a wildland fire problem (Cohen 2000; Calkin et al. 2014). The damaged home data were in line with this view, with few homes showing evidence of continuity with wildland fuels that would contribute to flame impingement, but numerous homes with near home fuels, both from manmade and natural sources, that led to direct or indirect ember ignitions.
California’s Mediterranean climate will continue to challenge its residents with regular wildfire exposure throughout the state. Whether through modifying the nearby surface and vegetative wildland fuels or the home itself, adapting to wildfire will take time. The good news is that the trend in survival is improving with newer construction practices. However, with 56% of houses built after 2008 still succumbing to the Camp Fire, much room for improvement remains.
Our data suggest it is possible to build (and maintain) buildings that have a high probability of surviving a worst-case scenario type of wildfire, even in fire-prone landscapes such as the Paradise area. Newer homes built after 1972, where the nearest burning structure was >18 m away, and fuels associated with vegetation 30–100 m from the home kept at moderate and lower levels (<53% canopy cover) had a 61% survival rate—an approximately 5-fold improvement over the Paradise housing population as a whole. Survival percentages substantially higher still are potentially possible if all components of risk, including ember generation in nearby wildland fuels, continuity of wildland and other fuels on the property, and home ignitability are sufficiently mitigated.
Citation:
Knapp, E.E., Valachovic, Y.S., Quarles, S.L. et al. Housing arrangement and vegetation factors associated with single-family home survival in the 2018 Camp Fire, California. fire ecol 17, 25 (2021). https://doi.org/10.1186/s42408-021-00117-0
Fuel treatments, Lake Tahoe area, and perimeter of the Caldor Fire Sept. 1, 2021.
For decades land managers and some residents in the Lake Tahoe area have been anticipating the Caldor Fire that has been burning since August 14. The blaze has blackened more than 204,000 acres as it rages to the northeast. It passed through the south edge of Meyers six miles south of the lakeshore and the head of the fire Wednesday morning was four miles from the lake.
Under the concept of reducing the fire threat to structures in the Lake Tahoe Basin, the US Forest Service and other organizations have been conducting hazardous fuel treatments. Since 1997, over 2,000 acres of landscape underburns and over 8,000 acres of prescribed pile burning has been completed on the Lake Tahoe Basin Management Unit (LTBMU), a division of the USFS that manages much of the land near the lake. In these areas, surface fuels have been reduced and smaller live trees thinned. The USFS says this “creates a zone where a damaging crown fire is less likely, which provides a safer environment for firefighters.”
The map above shows the fire on the morning of September 1 and completed hazardous fuel treatments. The green areas represent mechanical methods, such as thinning by hand or by using machines such as dozers or feller bunchers which can rapidly gather and cut a tree before felling it. Then the cut vegetation is piled. The purple areas represent locations where piles were burned. Some of the projects shown were completed in the last few years and others are older. This map shows very few areas (in yellow) that were treated with prescribed broadcast fire.
The USFS web page for the LTBMU politely says that budget restraints limit the number of acres that can be treated: “Increasing the annual number of acres treated with prescribed fire will challenge our future capacity.”
USFS engine crews on the initial attack of the Caldor Fire, August 14, 2021. USFS photo.
The hope is that reducing the flammable vegetation will reduce the chances of structures being destroyed when a fire like the Caldor Fire burns into the area. Thinning trees and removing brush will not stop a fire, but in a best case scenario under benign weather and fuel conditions it might reduce the intensity of the fire and the number of firebrands landing on and near structures. If a fire does dramatically slow down when entering a treated area, it may make it possible for firefighters on the ground, perhaps aided by firefighters in the air, to stop the spread. That is, unless the wind is too strong and the vegetation moisture is historically low like we have seen this summer in California. As we wrote on August 22, under these conditions, “There is no possibility of stopping the forward spread of the fire. There is no number of 747 air tankers or firefighters on the ground that could be effective against the flaming front of this raging inferno.” This will continue to be true until something changes — some combination of cooler more humid weather, less wind, and vegetation with higher moisture content — or until it runs out of fuel at high elevations or spreads into agricultural land.
The Caldor has been lofting burning embers into the air that have landed a mile ahead of the flaming front, starting new fires, called spot fires by firefighters. When that is occurring fuel reduction projects a half mile wide around a community will not necessarily keep structures from burning. We could pave the forest paradise and put up a parking lot but if a fire a mile away can ignite residences we need other solutions.
The Home Ignition Zone (HIZ) is what home owners need to concentrate on. If it is welcoming to an ember storm, then the structure could burn no matter how much forest management is done. The HIZ must be maintained so that burning embers will not start a fire on the structure or ignite nearby vegetation which creates a fire that spreads to and ignites the building.
This is called Living With Fire. We can’t stop fires from burning, but we can stop homes from igniting when the inevitable fire occurs.
The best way to prevent homes from being destroyed in a wildfire is not clear cutting or prescribed burning a forest, it is the homeowner reducing flammable material in the HIZ. This includes spacing the crowns of trees at least 18 feet apart. The envelope of the structure itself must be fire resistant, including the roof, vents, siding, doors, windows, foundation, fences, eaves, and decks. A FEMA publication (13 MB) has excellent detailed recommendations. Headwaters Economics found that the cost of building a fire-resistant home is about the same as a standard home. When implemented, Chapter 7A of the California Building Code, regulates these features.
Here is an excerpt from an article written by Jack Cohen and Dave Strohmaier:
Uncontrollable extreme wildfires are inevitable; however, by reducing home ignition potential within the Home Ignition Zone we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem. Unfortunately, protecting communities from wildfire by reducing home ignition potential runs counter to established orthodoxy.
UPDATE September 3, 2021:
In a live briefing Sept. 3 about the Caldor Fire near South Lake Tahoe, California, East Side Incident Commander Rocky Oplinger complimented the land owners and managers for the fuel treatments that have been accomplished over the years. He said the 150-foot flame lengths dropped to about 15-feet when the fire entered the treated areas. This allowed hand crews and engines to take an aggressive approach to suppress the fire and prevent structure loss. The video of the briefing is on Facebook; Mr. Oplinger’s comments about the fuel treatments begin at 34:10.
Devastation from the Almeda Drive Fire in the area of Phoenix and Talent in southern Oregon. Screenshot from video shot by Jackson County on September 8, 2020.
The traditional way — and the easiest way — to compare wildfire seasons is the number of acres burned. That figure is fairly straightforward and reliable, at least for data within the last 35 years; before 1984 the data is questionable.
But blackened acres does not tell the whole story about the effects of fires on humans. A 50,000-acre fire in a northwestern California wilderness area has fewer direct impacts on the population than, for instance, the 3,200-acre Almeda Fire that destroyed 2,357 residences in Southern Oregon a few months ago.
Top most destructive wildfires in the United States. Headwaters Economics.
Headwaters Economics has built a user friendly interactive data base of the number of structures, by state, destroyed by wildfires from 2005 to 2020. It presumably includes all structures, including back yard sheds, other outbuildings, commercial buildings, and residences.
Here are three screenshots, examples for the entire U.S., Colorado, and Montana.
Top most destructive wildfires in Montana. Headwaters Economics.Top most destructive wildfires in Colorado. Headwaters Economics.
The best way to prevent homes from being destroyed in a wildfire is not clear cutting or prescribed burning a forest, it is the homeowner reducing flammable material in the Home Ignition Zone. This includes spacing the crowns of trees at least 18 feet apart that are within 30 feet of the home, 12 feet apart at 30 to 60 feet, and 6 feet apart at 60 to 100 feet. The envelope of the structure itself must be fire resistant, including the roof, vents, siding, doors, windows, foundation, fences, eaves, and decks. A FEMA publication (13 MB) has excellent detailed recommendations. Headwaters Economics found that the cost of building a fire-resistant home is about the same as a standard home. When implemented, Chapter 7A of the California Building Code, regulates these features.
Uncontrollable extreme wildfires are inevitable; however, by reducing home ignition potential within the Home Ignition Zone we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem. Unfortunately, protecting communities from wildfire by reducing home ignition potential runs counter to established orthodoxy.
It would appropriate $300M annually for the federal land management agencies’ prescribed fire programs. But are there other ways to reduce fire risk?
September 24, 2020 | 8:10 a.m. MDT
Prescribed fire at Chickasaw National Recreation Area in Oklahoma by M. Fidler, February, 2013.
A bill has been introduced in the U.S. Senate that would make large sums of money available to increase the number of acres treated with prescribed fire (also known as controlled burns).
It has been fashionable during the last two years to blame “forest management” for the large, devastating wildfires that have burned thousands of homes in California. According to a 2015 report by the Congressional Research Service the federal government manages 46 percent of the land in California. The California Department of Forestry and Fire Protection manages or has fire protection responsibility for about 30 percent.
Research conducted in 2019 to identify barriers to conducting prescribed fires found that in the 11 western states the primary reasons cited were lack of adequate capacity and funding, along with a need for greater leadership direction and incentives. Barriers related to policy requirements tended to be significant only in specific locations or situations, such as smoke regulations in the Pacific Northwest or protecting specific threatened and endangered species.
The National Prescribed Fire Act of 2020, Senate Bill 4625, which was introduced last week by Senator Ron Wyden of Oregon and two cosponsors, would help address the capacity issue by appropriating $300 million for both the Forest Service and the Department of the Interior (DOI) to plan, prepare, and conduct controlled burns on federal, state, and private lands. It would also provide $10 million for controlled burns on county, state and private land that are at high risk of burning in a wildfire. Additionally, the bill establishes an incentive program that would provide $100,000 to a State, county, and Federal agency for any controlled burns larger than 50,000 acres. (Summary and text of the bill)
In order to carry out the projects, the legislation would establish a workforce development program at the Forest Service and Department of the Interior to develop, train, and hire prescribed fire practitioners, and creates employment programs for Tribes, veterans, women, and those formerly incarcerated.
In an effort to address air quality control barriers, the bill “Requires state air quality agencies to use current laws and regulations to allow larger controlled burns, and give states more flexibility in winter months to conduct controlled burns that reduce catastrophic smoke events in the summer.” The legislation will allow some prescribed fire projects larger than 1,000 acres to be exempt from air quality regulations.
Our Take
Appropriating more funds and hiring additional personnel for conducting prescribed fires could definitely result in more acres treated. If the bill passes, it would be a large step in the right direction. It is notable that the bill specifically mentions hiring those who were formerly incarcerated. Those who served time for non-violent offenses often deserve another chance, especially if they learned the firefighting trade on a state or county inmate fire crew.
There are many benefits of prescribed fires, including more control over the adverse health effects of smoke, improving forest health, and returning fire to dependent ecosystems.
But it gets complicated when prescribed fire is expected to “…help prevent the blistering and destructive infernos destroying homes, businesses and livelihoods”, as cited in a release issued last week by the Senate Committee on Energy and Natural Resources.
One provision of the bill is poorly worded and is confusing. In Section 102 it is either saying that no later than September 30, 2022 every unit of the USFS, FWS, NPS, and BIA must conduct a prescribed fire larger than 100 acres, possibly only applying to units west of the 100th meridian. Or, it might be interpreted as meaning each unit larger than 100 acres must conduct at least one prescribed fire. But either way it is ridiculous and arbitrary. Some 100-acre units might never be suitable for prescribed fire. Planning to use fire as a tool is based on science and the determination that treating an area with fire is PRESCRIBED in order to accomplish a number of specific objectives, not well-meaning but possibly detrimental legislation.
Scenario #1, Moderate fire conditions
There is no doubt that if a wildfire is spreading under moderate conditions of fuels and weather (especially wind), when the blaze moves into an area previously visited by any kind of fire the rate of spread, intensity, and resistance to control will decrease. Firefighters will have a better chance of stopping it at that location. The size of that earlier fire footprint will be a factor in the effectiveness of stopping the entire fire, since the wildfire may burn through, around, or over it by spotting. The availability of firefighting resources to quickly take advantage of what may be a temporary reduction in intensity is also critical. Unless the prescribed fire occurred within the last year or so there is usually adequate fuel to carry a fire (such as grass, leaves, or dead and down woody fuel) depending on the vegetation type and time of year. It is much like using fire retardant dropped by air tankers. Under ideal conditions, the viscous liquid will slow the spread long enough for firefighters on the ground to move in and put out the fire in that area. If those resources are not available, the blaze may eventually burn through or around the retardant.
Scenario #2, Extreme fire conditions
The wildfires that burn hundreds or thousands of homes usually occur during extreme conditions. What the most disastrous fires have in common is drought, low fuel moisture, low relative humidity, and most importantly, strong wind. In the last few weeks in California and Oregon we have seen blazes under those conditions spread for dozens of miles in 24 hours.
Rich McCrea, the Fire Behavior Analyst on the recent North Complex near Quincy, CA, said the wind on September 8 pushed the fire right through areas in forests that had been clear cut, running 30 miles in about 18 hours.
We can’t log our way out of the fire problem.
Burning embers lofted by the Creek Fire are seen as people are sheltering at the Mammoth Pool Reservoir Boat Launch, Sept. 5, 2020 in Northern California. Photo by Cameron Colombero, via Mike Ikahihifo.
On September 8, 2020 the Almeda Drive Fire burned 3,200 acres in Southern Oregon — it was not a huge fire, but there were huge losses. The 40 to 45 mph wind aligned with the Interstate 5 corridor as it burned like a blowtorch for 8 miles, starting north of Ashland and tearing through the cities of Talent and Phoenix. Approximately 2,357 structures were destroyed — but not all by a massive flaming front. Burning embers carried up to thousands of feet by the fire landed in receptive fuels near or on some structures, setting them alight.
A portion of the Almeda Drive Fire in the area of Phoenix and Talent in southern Oregon. Screenshot from video shot by Jackson County on September 8, 2020.
What can be done to reduce fire losses?
Jack Cohen is a retired U.S. Forest Service Research fire scientist who has spent years determining how structures ignite during extreme wildfires. In a September 21, 2020 article he wrote for Wildfire Today with Dave Strohmaier, they addressed how homes ignite during extreme wildfires.
“Surprisingly, research has shown that home ignitions during extreme wildfires result from conditions local to a home. A home’s ignition vulnerabilities in relation to nearby burning materials within 100 feet principally determine home ignitions. This area of a home and its immediate surroundings is called the home ignition zone (HIZ). Typically, lofted burning embers initiate ignitions within the HIZ – to homes directly and nearby flammables leading to homes. Although an intense wildfire can loft firebrands more than one-half mile to start fires, the minuscule local conditions where the burning embers land and accumulate determine ignitions. Importantly, most home destruction during extreme wildfires occurs hours after the wildfire has ceased intense burning near the community; the residential fuels – homes, other structures, and vegetation – continue fire spread within the community.
“Uncontrollable extreme wildfires are inevitable, however, by reducing home ignition potential within the HIZ we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem.”
"Community wildfire risk should be defined as a home ignition problem, not a wildfire control problem." Jack Cohen and Dave Strohmaier.
Again, prescribed fire has many benefits to forests and ecosystems, and Congress would be doing the right thing to substantially increase its funding.
But in order to “…help prevent the blistering and destructive infernos destroying homes, businesses and livelihoods”, we need to think outside the box — look at where the actual problem presents itself. The HIZ.
I asked Mr. Cohen for his reaction to the proposed legislation that he and I were not aware of when the September 21 article was published.
“Ignition resistant homes, and collectively communities, can be readily created by eliminating and reducing ignition vulnerabilities within the HIZ,” Mr. Cohen wrote in an email. “This enables the prevention of wildland-urban fire disasters without necessarily controlling extreme wildfires. Ironically, ignition resistant homes and communities can facilitate appropriate ecological fire management using prescribed burning. The potential destruction of homes from escaped prescribed burns is arguably a principal obstacle for restoring fire as an appropriate ecological factor. Therefore, it is unlikely that ecologically significant prescribed burning at landscape scales will occur without ignition resistant homes and communities.”
Here are some suggestions that could be considered for funding along with an enhanced prescribed fire program.
Provide grants to homeowners that are in areas with high risk from wildland fires. Pay a portion of the costs of improvements or retrofits to structures and the nearby vegetation to make the property more fire resistant. This could include the cost of removing some of the trees in order to have the crowns at least 18 feet apart if they are within 30 feet of the structures — many homeowners can’t afford the cost of complete tree removal.
Cities and counties could establish systems and procedures for property owners to easily dispose of the vegetation and debris they remove.
Hire crews that can physically help property owners reduce the fuels near their homes when it would be difficult for them to do it themselves.
Provide grants to cities and counties to improve evacuation capability and planning, to create community safety zones for sheltering as a fire approaches, and to build or improve emergency water supplies to be used by firefighters.
